1. Field of the Invention
The present invention relates to a method of assembling a vehicle seat such as an automotive seat, and in particular to the seat assembling method in which a foam cushion member is formed in a mold and then a trim cover assembly is bonded by adhesive to the cushion member.
2. Description of Prior Art
Among various seat assembling methods, there has been known a method utilizing a location board to precisely bond a trim cover assembly over a foam cushion member. The location board is sewn together with the trim cover assembly at its juncture points, such that the board stands vertically such as to be engaged into recessed grooves of cushion member at upper die side and those of lower die. Specifically, a conventional example of such seat assembling method is shown FIGS. 1, 2 and 3.
As shown in FIG. 1, there are provided an upper die (U') and a lower die (L') such that the upper die (U') is movable vertically toward and away from the lower die (L') At the upper die (U'), a foam cushion member (P') is secured, which is pre-formed by a foaming process using a mold in a predetermined shape of seat cushion; namely, a seat cushion body having, formed therein, a pair of lateral raised portions (33')(33') (i.e. bolster portions) and a flat central seating portion (34') defined between the two lateral raised portions (33')(33'). At respective boundaries between the central and lateral raised portions (33')(33'), recessed grooves (32)(32) are formed for a purpose to be set forth later. On the other hand, a trim cover assembly (C') is turned upside down and placed upon the lower die (L') having a working surface contoured in a shape conforming to the foregoing outer shape of cushion member (P'). The trim cover assembly (C') is composed of a central cover section (11') and a pair of lateral cover sections (12')(12' ). The lateral cover sections (12') are at their one ends sewn to both lateral ends of central cover section (11'), respectively, via two location boards (2)(2) as shown in FIG. 2. Although not clearly shown, each of the location boards (2) (2) is formed in a long tape-like strip manner, and made of a hard synthetic material.
Looking again at FIG. 2, one end, as designated by (12'a), of the lateral cover section (12') and one end, as designated by (11'a), of central cover section (11') are shown as sandwiching the first half (22) of location board (2) and being sewn by threads (41) to the respective opposite surfaces of the board (2), while another second half (21) of board (2) is inserted in the location groove (33) formed in the lower die (L'). Hence, the location board (2) is fixed along the boundary line between the central and lateral cover sections (11')(12') and erected there vertically at a right angle relative to surface of the lower die (L'). FIG. 2 is a view to enlarge the portion encircled by designation (A), showing only left-side juncture between the two cover sections (11')(12') but it should be understood that another right-side juncture is constructed as such, as viewed from FIG. 1. Therefore, a pair of location boards (2) are disposed upon the lower die (L') as seen in FIG. 2, such that the first halves (22) of the boards (2) project upwardly while the second halves (21) thereof project down and rest within the respective location grooves (33) of lower die (L'). With the boards (2)(2) set as such upon the lower die (L'), the trim cover assembly (C') is secured on the same die, as in FIG. 1, the upper die (U') is lowered towards the lower die (L') to pressingly bond the cushion member (P') to the rear surface of trim cover assembly (C'). At this point, the upper first halves (22) of location boards (2), with the juncture part (i.e. 11'a, 12'a) or trim cover assembly (C') sewn to those first halves (22), are respectively inserted and bonded in the two recessed grooves (32)(32) of the cushion member (P'). After completion of such bonding, a bonded unit of cushion member (P') and trim cover assembly (C') are removed from the upper and lower dies (U')(L'). Then, as shown in FIG. 3, the second halves (22) of location boards (2), which project outwardly from the upper surface of trim cover assembly (C'), are cut off, as a result of which a seat is produced.
However, the location boards (2) are formed in a long strip form on a straight line, which means that the boards (2) are only effective for application to such seat cushion having the flat central portion (34') with the connection line or boundary line between the central and lateral cover sections (11)(12) extending straightly. As a consequence thereof, where the corresponding central seating portion of a cushion member is formed uneven or curved vertically in the seat cushion and the working surface of lower die is shaped conforming to such vertical curvature, then the straight location board is not deformed accordingly and if a trim cover assembly with such straight board is bonded to the cushion member by the lower die and upper die, the trim cover assembly is not wholly bonded over the cushion member, creating a floated non-bonded part or unpleasant wrinkles in the trim cover assembly.